Wheel chock



A. c. RIIIDLAND I WHEEL OHOCK Filed July 22, 1946 2 Sheets-Sheet l v@fEIIEIIIZEIeZ E- f' Jaw/5.272 771" Juan der 5!: az-lesflz'dlazvi July5, 1949. v 'A. c. RIDLAND 2,475,111

vmm. cnocx Filed July 22, 1946 2 Sheets-Sheet 2 Patented July 5, 1949UNITED STATES PATENT OFFICE 23 Claims.

This invention is concerned with a wheel chocking device for temporarilyblocking vehicle wheels against rolling. A primary object of myinvention is to produce a sturdy and effective wheel chock which can befolded into a relatively compact form when not in use. My inventionfurther provides a mechanism which is light in weight and easy tomanipulate, and which operates reliably when used on rough ground aswell as on a smooth surface. At the same time my wheel chock has astructural simplicity well adapted for economical manufacture. All ofthese characteristics make it particularly well adapted for use withlight aeroplanes, but my invention is not limited to this particularapplication.

Further objects and advantages of my invention and a full understandingof its nature will be appreciated from the following description of anillustrative preferred embodiment and of certain modifications thereof.This description is to be read in conjunction with the attacheddrawings, of which:

Fig. 1 is an elevation of an illustrative wheel chock, according to myinvention, in position under a wheel;

Fig. 2 is a similar elevation of the chock in its folded position readyfor stowing;

Fig. 3 is a partially cut-away plan view of the chock in its foldedposition;

Fig. 4 is a perspective sketch of the device in operating position;

Fig. 5 shows a fragmentary plan View, similar to Fig. 3 but includingonly one end portion, showing an alternative manner of constructing thechock members;

Fig. 6 is a fragmentary perspective, showing a second alternative formof the chock members;

Fig. 7 is a side elevation of a modified form of my chocking device, inposition under a wheel;

Fig. 8 is a side elevation similar to Fig; 7, but showing the device inits folded position;

Fig. 9 is a partially cut-away plan view, corresponding to Fig. 8;

Fig. 10 is a transverse section of the folded device taken on linel0--l0 of Fig. 9;

Fig. 11 is a perspective view of the modified wheel chock in operatingposition; and

Fig. 12 is an enlarged fragmentary section on line i2--l2 of Fig. 9,showing preferred structure of friction treads on the chock plates.

My wheel chocking device comprises primarily an extensible frame 12including chock carriers I6, supporting chocks 20 which are adapted toengage the periphery of the wheel I0 to be checked. The chock carriers[6 are urged toward each other by suitable tension means, maintainingthe chocks in firm contact with the wheel. To facilitate stowing whennot in use, chocks 20 are hinged or pivoted to chock carriers l6 and arereleasably locked in their operating position (Figs. 1 and 4) by thebraces 25.

In the embodiment illustrated in Figs. 1 to 4 chocks 20 are formed ofsingle pieces of tubing, bent as indicated in the drawings, with aconcave curve on their swinging ends, giving surfaces at 2| adapted toengage the rubber tire of an airplane wheel. The tube ends are flattenedat 23 and drilled to form pivot bearings. Chock carriers l6 are alsosingle pieces of tubing, formed by a single sharp right angle bend orangle at 11 into an L-shape, of which one leg l6a constitutes the chockpivot pin. The chock is restrained axially upon pivot IBa by anysuitable means such as the cotter pins Ill. The other leg 16b of eachL-shaped chock carrier l6 enters an end of guide tube l3, which thusserves to join the two chock carriers and to guide their relativemotion. This motion of chock carriers I 6 and their carried chocks 20 isof two types: unrestricted rotation relative to tube 13 and to eachother about the tube axis; and axial sliding motion within tube 13,limited and controlled as described below. Central guide tube l3 andchock carriers It thus flexibly linked to it comprise the essentialstructure of the extensible frame [2 mentioned above. It ,will beobvious, however, that the entire structure illustrated can be modifiedin many respects without departing from the scope of my invention.

Chock braces 25 are shown as simple rods, their upper ends 25a bent atright angles and pivoted in holes 26 in chocks 2D; and their lower ends25b similarly bent and slidingly pivoted in the slots 21 cut through thewalls of tubular legs l6b of chock carriers l6. Within tubes Hib the twobrace ends 251) are connected to each other by spring 30 and also(preferably) by a flexible cable 31, both of which are preferably, butnot necessarily, anchored midway of their lengths to the transverse pin32 centrally placed in guide tube 13. Due to the general symmetry of thedevice, the two functions performed by spring 38 of urging brace end 25band chock carrier it toward guide tube 13 will be performed in much thesame manner whether spring 30 is anchored to tube l3 or not.

Spring 30 urges the sliding motion of brace ends 25b in slots 21 in thedirection toward slot ends 21a; and also, once the brace contacts theslot end, urges the inward sliding motion of chock carriers It in guidetube I 3. While the described structure thus permits the single spring30 to perform two distinct functions satisfactorily, this does notprevent the use of separate spring means, if desired to urge chockcarriers l6 together independently of the motion of the chock braces.Inward motion of the chock carriers is limited by contact of the end oftube [3 with brace end 2519 Where it enters-slot 21;; andis limitedoutwardly by cable 3!; which. isnormally slack; but which is shortenough to prevent leg I61) of chock carrier Hi from being removedcompletely from guide tube 13. If the outward motion of chockbarriers 29is suitably limited by other means, cable 3! can of course be omitted.

Sliding motion of brace end 25b in slot 21 .in the direction toward slotendZlaraises 'chock'2fl to its operating position (Figs. 1 and 4)whi1ermotion in the opposite direction lowers it to its fold- .-,.ed.position- (Figs. 2..and 3). .The. end 21a of slot This solocated, thatit stops the spring urged sliding motionof brace .2 i-whenl the latteris approximately .vertical -and hence-when the chock isvfullyfraised.Since,the1.directionof brace .25 r isthen nearly normalrto slot. 2l,..whatever thrust the braceis ,requiredtp: transmit from chock. 26 tochock; carrier-J fi can'havepnly asmall-compo- --nent-;parall el to the;slot. .=-10nly m oderate tension :ofspringrttis therefore requiredtohold the brace firmly rin, chocle supporting position against :theend-Elwoftheslot. ably so -placed,thatbrace525 .isislightly-pastvertical', asrindicated in'j-Eig; 1. -.,-Downward;thrust .onthe bracethen tendslio holdit more tightly against the slot ,end,.-. minimizingthezdanger. of

the brace-being accidentally-displaced from'its chock; supportingposition.

The slot end 210,115 prefer- 2=The wheeleng-aging-isurface 2|:1of:thechock is .on.the swinging: endxof the-chock,- :and; when the -device:-is; in, use,this-.:.surface.- lies? generally. .be-

tween v,wheel axis llxand chockraxisfl :andclose such factors asfriction Land: the: size shape. and

structure. OfUthBEWhBG]. .tire. .-.Accordingly, my 1 wheel chock: is"preferably'so constructed that" the chockingelem'entsfw in s'operatingtposition pro-. jectixabove the;.plane. Zdefined :-.by.".wheel axis J! land chock. axis '32 2.:3at- .such: an. angle that the resultant: thrust:of the wheel :upon i'ChOCk surface 2 I will bezidi-rected capproximatelytoward richock axis 22. The: thrust. :then :has. a'.relativelyx-ilargecomponentr'in 'the'ipIaneLof;thelchock, and a relatively. small.compohentt;perpendicular. t. 1 this plane. The larger-component istransmitted through the :chock. axi's toi the ground; and i only thesmallerxzompcnen'tissupportedbyibrace.25.

Accordingly; choekrbrace' fi serves primarily to hold chock 20 in itschockingpositi'on; and-does not itself sustainthemain; thrust-.rofithe;'cho'cked fwheel .10.

:of: the :exact typexforqwhich a igiveni'chocking' .de-*

This:is:tr.ue; ideallwonly for a wheel vice is specifically designed.However, there is no need for the condition described to be satisfiedaccurately, and in practice a chocking device of given size caneffectively accommodate a consid- 5 erable range of wheel sizes.Transmission of the wheel thrust through the chock to the ground may bevia carriers l6 which may be provided with ground engaging means; but ispreferably through the chocks themselves, which, for this 10 purpose,may have sharp cornered square ends.

In the folded positionof Figs. Z'and 3 the chocks and their braces 25lie substantially in the nsame plane, and spring 30 holds brace ends25%; against the ends of tube i3. In this folded posi- "tion the springthus has no tendency to raise the :chocks. To :raise the chocks andprepare the device for. use it is only necessary to lift the checkstoward the position of Fig. 1 and to pull them outward. F This may beconveniently done by grasping the chocks at 2!; and pulling up and out.;.-Dl) lil1g tl1at, operationbrace endszb will remain .efigainst-theends-of-tube cl3 as carriers I I6 slide .outwarddn. tubeqlSuntil-tha-slotends 210, are pulled .outegainst brace'ends .-25b and thechocks 5 areifully raised. v-Further :ou-tward movement of the checksandcarriersis then opposedby spring 68. 'Separation of chockoarriersi lBis continued, distending-springfiil;until cable 3i becomes taut oruntil the. clearanceybetween the upper. extremes :,of ,thetwcnchocks-lflis sufficient,:.to'-:receive the wheel slllheldevicesis thenuinsertedbeneath "wheel 56,:andr5pring 30-;is:a'llowed to=.draw.chock carriers".5 fictogetheruuntil :chocksi .Eiltengage the I ..:periphery ofithewheel. izSpringa'dll firmly-maintains thisrengagementg andatithesame time holds brace ends 25b in contact with slot ends 2111,effectively .lo cking; therbraces shock I support- .ing position.iiltqmay-benoted that if the wheel to. be chockedeisztoo, large .toallow:the procedure 0 .just. described;-.the sdevice may-Jstillbe used by:slidingcit into positionmwith chock carriers l6 .zfully. separated, butwith'chocks126 held fiat as in Fig. 2 until after they are underthewheel.)

:The .cho'c'king device :can: be. withdrawn-from :under. the wheel. byfirst separating chock carriers it against the force of spring iifi. fThe de- ....vice isithentfolded' by. simply telesco'pingchock carriersIt togetheritvithinrguide tube-"l3. When the ends'ofthistube-contactbra'ce ends 25b, still in the position showm-iIi -Fig 1these are forced to :slide ialong islets- 27, automatically foldingchocks 20, and completing the-preparation for istowing.

Sin'ce the device-as"illustrated-in Figs. 1 to 4 is 55. symmetrical withrespectto" the plane of base frame [2 (in its normal position);itis-immate- "rial; to which side or: this 'plane chocks 2 0 swingwhenthey-are unfdlded;- so'longas both swingto "the same s'ide.Thiscanyof course, be arranged readily by slightmanu'alpressure upon thechocks -as chockccarriers ilfi are iirst drawn apart. The symmetryreferred tois not necessary to my invention; 'an'c'l'canbe modified: tosuit special requirements. For example, .inthe particular em- .65-bodiment here illustrated; :the' two-corners 230.

and 23b of the fiattened chock tube ends 23 can be shaped differently:to suit idifferent types of ground. :The cho'cks. can then be swung toone side or the "other 'of baseztrame l2 to bring the --desiredformation at -23-into use.

As has already been noted; the chock carrierswith 'theirlchocks. are Efreeto rotate about i'theaxis of guide tubel3. P-his rotation'offers:the great;advantage of allowing "the two chock 'carriersito" assumedifferent angles when used on rough ground, thus conforming to thesurface and rendering the chocking action more positive and reliablethan if the entire structure were rigid.

Although the device has been described as including, and preferably doesinclude, two oppositely disposed chocks and carriers, a single chockdevice which is in substance one-half of the described two-chock devicemay be used for some purposes. Such a single chock device would embodysubstantially those parts which are shown in say the left-hand half ofFig. 3, with the spring so in this case necessarily anchored at itsrighthand end to tube l3.

The chocks can of course be formed in many ways other than thatillustrated in Figs. 1 to 4. For example, as illustrated in Fig. 5, theymay retain their general tubular form but be pivotally mounted on chockcarriers It by means of tube sections 4!] which fit over the carrierarms lfia and act as pivot bearings. A second alternative form of chock,illustrated in Fig. 6, consists of a single sheet metal stamping 45,which may have appropriate strengthening flanges 46 and channels ll anda flanged wheel contacting surface Such a stamping can include a sleeveforma ticn as indicated at 49 to act as a pivot bearing for carrier armlea. I do not intend that these particular forms of chock constructionillustrated be construed as a limitation of the scope of my invention.

When my chocking device is used on a smooth surface such as a concretefloor, particularly if it is used with a wheel of relatively smalldiameter, the wheel may have a tendency to slide the chock over thefloor. This is because the direction of thrust of the wheel against thechock makes a relatively small angle with the surface of the floor,giving a relatively large horizontal component and a relatively smallvertical frictionproducing component. This tendency can be reduced bythe use of chock plates, such as are included in the modification of myinvention illustrated in Figs. 7 to 12. Besides the use of chock plates,this modification illustrates how one chock carrier can act as framemember to support the other, eliminating the central frame member I3 ofFigs. 1 to 4.

The fundamental structure and operation of this modification are thesame as in that already described. However, the coaxial tubular legs ofthe chock carriers 56 and 51 are longer than before and are of differentdiameter sothat one can slide within the other. The telescoping motionof one tube within the other is limited inwardly by contact of the endof each tube with the end 652; of the check supporting brace 65associated with the opposite carrier; and outwardly by any suitablemeans such as cable 68 connecting the two brace ends. The tension spring69, attached to the two brace ends, urges them together, and also urgestogether the two chock carriers when the braces are in contact with theinner ends 61a of slots 61. The operation of chock supporting braces 65to raise and lower the chock members 66 is the same as in the firstdescribed modification, with the slight distinction already mentionedthat each brace end is pushed outward as the device is folded by the endof the opposite chock carrier rather than by the end of a central guidetube.

This form of my device, besides eliminating the central guide tube,allows somewhat greater longitudinal flexibility of the device, thusallowing it to embrace a larger wheel or fold to a more compact size orboth. It will be evident that with 6 this form there is no need ofcentrally anchoring spring 69 and cable 68.

The chock plates 15 are shown in Figs. '7 to 12 as steel Dressings.These are essentially fiat but have strengthening flanges it along theirsides and friction ridges 71 on their upper faces. These ridges can beformed, as shown in Fig. 12, like the well-known louvre openings such asare frequently used to provide ventilation. Chock plates 15 are securedto the remainder of the structure only at their outer ends which arepivoted to the upper ends of chocks 66 for rotation about axes parallelto those of the chock pivots 56a and 51a. Preferably the pivot axes ofthe chock plates are formed simply by extensions of the upper ends 65aof chock supporting braces 65, as shown most clearly in Fig. 9.

In operating position under the wheel chock plates it are supported attheir upper ends by these pivots, and their lower ends rest directly onthe ground, as shown in Fig. 7. They are so proportioned that as thewheel starts to roll the tire presses downward on the lower part of thechock plate. The direction of this thrust being nearly vertical, itcreates a strong frictional resistance to slipping at its surface ofcontact with the ground. This prevents the entire device from sliding.The main thrust of the wheel is transmitted from the upper portion ofthe chock plate through pivot 65a to the check itself and, as before,longitudinally through the chock to the ground.

When the device in its present form is folded the projecting ears Blwelded to the sides of chock plates 15 contact the upper surface of thechock carriers and force the plates to rotate about pivots 6504 into theplane of chocks 66, as shown in Fig. 8. The plates are prevented fromturning beyond this position by contact with stops i8 welded to thecross members Sta of the checks. Thus when folded, the position of theplates is restricted by stops 18 on the one hand and ears 8! on theother, insuring a compact form of the entire device. As the chockcarriers 55 and 51 are telescoped together one chock plate partiallynests inside the other. To facilitate this nesting one plate is madeslightly wider than the other, as can be seen clearly in Fig. 9, and oneof the ears 8! is preferably attached to its plate in a slightly higherposition than the other, as is shown in Fig. 8. Ears 8! are preferablyso located on the chock plates that in operating position they are wellclear of the chock carriers, as in Fig. 7, so that the swinging ends ofthe plates are supported only by contact with the ground or floor.

Various other changes and modifications may be made from theillustrative designs which have been described without departing from myinvention, the scope of which is defined in the following claims. Inthese claims I use the term telescopic, with relation to frame member l3and carrier in, or with relation to two carrier members such as 56 and51', to denote capability of relative extensive and contractivemovement, whether or not one member slides with relation to the other,or, if it slides, whether or not the two members are relatively slidingtubes. For instance, it is suflicient to the described functioning of mydevice that the chock carriers be movable in contractive and extensiverelation to the member called the frame or with relation to each other.And if that movement is one of sliding, the sliding association of theframe and carrier 75 maybe of any suitable formation, although a aetsn 11 tubular formationis preferable for simplicity-and for the flexibilitywhich has been noted? When one chock carrieris related directly "to theother without any intervening" frame= member each carrier is to beconstrued as forming a frame for theother. Andl may also-note-that,if-atubular or similar sliding formation is usedit is immaterial whetherthe --frame tubeor tliecarrier tube is the external one.

I claim:

1. In a device for checking a wheel; two-chock carriers telescopicallyrelatedfor longitudinal relative motion between relativelycontracted-and extended positions and also=forrelative swivellingmovement about a longitudinal ax-la a--cho'ck swingably mounted oneachcarrientd swing about a transverse chock axis betWe'en'a -folde'dposition essentially ina longitudinal plane-and an operatingposition-projecting abovethat plane, and chock holding memberseachassociatedwith a chock and the corresponding carrier' and adapted tohold the check in its operating "position.-

25A device as defined in claim-'1, and-alsoim cluding a frame memberextending longitudi nally between the twochock carriersand-telescopically andswivelly related to each'carrie'r.

3. In a-device for shocking a wheel"; two chock carrierstelescopicallyrelated for longitudinal relative motion between relatively contractedand extended positions, a chock swingably =m'ounted on each carrier toswing about a transverse chock axis between a foldedpositionessentiallydn a longitudinal plane and an operating positionin'a plane projecting upward -from the-long-itudinal plane, and meansacting betweeneachchock and its corresponding carrier to support'thchock in its operating position.

4. ma device for chocking a-wheek-two chock carriers telescopicallyrelated for I longitudinal relative motion betweenrelativelycontracted-and extended positions, a chock mounted on each carrier forswingingmoveinent about a transverse axis thereon between a foldedpositione-ssentially in-a longitudinal plane and an operating positionin a plane projecting upward frorn the'longi tndina-l plane and inward"fromthe said'axls, and means for releasably supporting checks in theiroperating positions.

In' a device for chock-ing-awheelftwo 'chock carriers telescopicallyrelated for longitudinal relative motion between relatively contractedand extended positions, chocks movably mounted on the carriers formotion relative thereto into "and out of operating positions, means "forreleasably confining the chocks in their operating positions; said meansbeing movable into and'out' of-chock confining positions, and meansassociated "with the chock confiningmeans and adaptedto move theconfining. means tochock confining'position by .virtue of motion of thechock carriers toward their relatively extended positions.

6. In adevice for chockinga wheeLtwo chock carriers telescopicallyrelated for.=longitudinal relative motio-nibetween relatively contractedand extended positions, chocks movably 'mounted on the carriers formotionrelative thereto into and out of operating positions, means for.zreleasably confining .the checks intheir' operating positions, saidmeansbeing movable into and :out of chock confining positions, and meansassociated :with therchock confining means and .lwithlzthe carriersandadapted 'Jzto' move the: carriers *out ofxtheir chockl' confiningpositions by virtue of inbtlon of the carrierstoward their relativelycontracted positions.

'7. In a device forchocking a wheel, two chock carriers telescopicallyrelated for longitudinal relative' motion betweenrelatively contractedand extended-positions, chocks movably mounted on thecar-riersfor-motionrelative thereto into and out 0f operating positions, meansfor releasably confining the chocks in their operating positions,

saidmeans beingmovable into'and out of chock confining-positions;springmeanstending to move the -chock-confining means into their chockconfining positions-andimeans for moving the chock confining means outof their chock confining positions by virtue of motion of the chockcarriers toward their relatively contracted positions.

8. In a' device for chocking a wheel, two' chock carriers telescopicallyrelated for longitudinal relative motion between relativelycontracted-and extended positions, chocks movably mounted on thecarriers for motion relative thereto into and out of operatingpositions, means forrelea'sably confining the chocks in theiroperatingpositions, said means being movable" into and out of chock confiningpositions; and unitary spring means tending to "move said chockconfiningmeans into theifchockconfining positions and tomove'the chockcarrierstoward their relatively contracted positions.

9.111 a device for checking a Wheel,a "frame member, a chock carriertelescopically-relatedto the frame member for longitudinal relativemotion between relativelypontracted and extended positions, achoc'kswingably mounted on'th car- "riento swing about a transversechock'axis beextended 1 positions 10."In"a device for checking a wheeLaframe member, a chock carrier telescopically related to the-frame memberfor longitudinal relative motion between-relatively contracted andextended positions, a chock swingably mounted -on the carrier to swingabout a transverse chock axis between 'a iolded position essentially in0. longitudi =nal-planeandi'an operating position projecting above-that*planareleasable means for holding the check in'a its operating positionwith relation 'to-= the a carrier; saidmeans movable betweenchock-holding .and chocl -'.releasingpositions, and meansassociatediwith the frame member-and the chockLholding means and-tendingto move the holding means to its chock-releasing i position-- by virtueof inovementof the carrier toward itscontracted position.

1t. cThelideviceidefined in claim 9 and in which sthexlas't-imenti'oned:means comprises a tie member connected between the holding means-andthe frameamember: l

12.?Thedevice defined -in1claim 9 and in which the lastzmen-tionedinea-nscomprises an extensible spring tie member connectedbetween theholding meanszandtheaframemember.

13.' The' deVi'ce' defined in claim '10, and also inclziding meansassociated-with the frame member and 'thei -lchock holdi'ng means and-tending to movethe-hol'ding means to its chock holding posi- 9 tion byvirtue of movement of the carrier toward its extended position.

Id. In a device for chocking a wheel, a frame member, a chock carriercapable of longitudinal motion relative to the frame member, a chockmounted on the chock carrier and rotatable about a transverse axisbetween a folded position essentially in a plane through said axis andparallel to said longitudinal motion and an operating positionprojecting out of that plane, a brace pivoted on the chock and slidablypivoted on the chock carrier for longitudinal sliding motion, a stoplimiting the said sliding motion at a point at which the brace is at anangle to the direction of said sliding motion and supports the chock inits operating position, and spring means tending to move the bracetoward the stop.

15. In a device for chocking a wheel, a frame member, a chock carriercapable of longitudinal motion relative to the frame member between arelatively extended position and a relatively telescoped position, achock mounted on the chock carrier and rotatable about a transverse axisbetween a folded position essentially in a plane through said axis andparallel to said longitudinal motion and an operating positionprojecting out of said plane, a brace pivoted on the chock and slidablypivoted on the chock carrier for longitudinal sliding motion, a stoplimiting the said sliding motion in a direction toward the frame numberat a point at which the brace is at an angle to the direction of saidsliding motion and supports the chock in its operating position, springmeans tending to cause motion of the brace toward the stop, and asurface on the frame member adapted to contact the brace and to causesliding motion of the brace away from the stop when the chock carrierapproaches its said telescoped position on the frame member...

16. A chocking device as defined in claim 15, and in which the springmeans comprises a spring attached at one end to the sliding end of thebrace and effectively attached at the other end to the frame member, sothat the spring tends to move the carrier toward its telescoped positionwhen said end of the brace is against the stop.

17. A chocking device as defined in claim 15,

and in which the frame member is in the form of a tube, and the chockcarrier in the form of a telescopically related tube, the spring meansbea tension spring lying within the two tubes and attached at one end tothe sliding end of the brace and effectively attached at the other endto the frame tube, and the end of the frame tube constituting thesurface on the frame adapted to contact the brace.

18. In a device for chocking a wheel, a frame tube, a chock carrier tubeadapted for longitudinal telescopic movement with relation to an end ofthe frame tube, a transverse axis member carried by the carrier tube, achock swingable about said axis member between a position substantiallyin the plane of the tubes and the axis member a position projecting fromthat plane, the carrier tube having a slot through its wall extendingfrom a slot closed end outwardly away from the end of the frame tube, achock brace pivotally connected at one end to the chock and having itsother end extending through said slot for pivotal and sliding movementtherein, and a spring located within the tubes and effectively connectedto the sliding end of the brace tending to move that end of the bracetoward the closed end of the slot.

19,. In a device for chocking a wheel, a frame 10 tube, a chockcarriertube adapted for longitudinal telescopic movement with relationto an end of the frame tube, a transverse axis member carried by thecarrier tube, a chock swingable about said axis member between aposition substantially in the plane of the tubes and the axis member anda position projecting from that plane, the carrier tube having a slotthrough its wall extending from a slot closed end outwardly away fromthe end of the frame tube, a chock brace pivotally connected at one endto the chock and having its other end extending through said slot for.pivotal and sliding movement therein, and a spring located within thetubes and effectively connected to the frame tube and the sliding end ofthe brace tending to move that end of the brace toward the closed end ofthe slot, and tending to move the carrier tube toward the frame tubewhen the brace contacts the slot end.

20. In a device for checking a wheel, a frame member having twolongitudinally opposite ends, two chock carriers telescopically relatedrespectively to the two frame ends, and adapted to move longitudinallyinwardly and outwardly with relation thereto between contracted andextended positions, a chock mounted on each carrier for swingingmovement about a transverse axis thereon between a position essentiallyin a longitudinal plane and a position projecting from that plane, abrace pivoted to each chock and pivoted slidably to the respectivecarrier to have 10ngitudinal sliding movement with relation to thecarrier, each carrier having a stop which limits the inward slidingmovement of the associated brace to a position in which the brace is atan angle to its directions of sliding movement on the carrier, andspring means acting effectively between the sliding ends of the twobraces tending to move them toward each other.

21. In a device for chocking a wheel, a ground engaging frame, twochocks mounted on the frame in longitudinally spaced relation andswingable about transverse chock axes between folded positionsessentially in a longitudinal plane and operating positions projectingabove that plane, the line of intersection of the planes of the twochocks in said operating positions lying above the said longitudinalplane, ground engaging chock plates mounted on the swinging ends of thechecks for pivotal movement about axes essentially parallel to the saidchock axes, said chock plates having ground engaging sur faces at theirswinging ends and being swingable between folded positions essentiallyin the planes of the chocks and operating positions at such an anglethat the line of intersection of the planes of the chock plates liesbelow the said longitudinal plane, and means for releasably supportingthe chocks in their operating positions.

22. In a device for chocking a wheel, a generally iiat frame, agenerally flat chock pivotally mounted on the frame for swinging motionabout a pivot axis which lies substantially in the plane of the frameand in the plane of the chock, the chock carrying a wheel engagingsurface generally transverse of the chock plane on one side of the saidaxis, and carrying two alternative ground engaging formations on theother side of the said axis and oppositely disposed with respect to theplane of the chock, said chock being swingable about the said axisbetween two operating positions substantially symmetrically disposed onopposite sides of the frame, and releasable means for confining thechock selectively in either of the said operating positions.

gaging.v chock plateswmonntedeon the swingin l0 ends of. the checks ionpivutaLmovement, about axes essentially pafalleljozthe said. ichock.axes, said chock, pl-atesahavingt round eng8igil1g1 surfaces attheirswinging .endstand being. swingable between -o1ded positions..essentiallydnlthe planes of the checks and operating nosltionsat suchan angle. that the line:ofiintersdti'onmiLthe planes .12 of. the .chock,plates eliesrbelowthevsaid longitudinal plane,'the swinging ends o.the.chock plates inntheiri operating positions being supported only byltheinground engagement... andmeans for vre- Ieasably, supportingthe.chocks in their operating positions.

. ALEXANDER CHARLES RIDLAND.

" REFERENCES :CIIED :The following references are-of record in thefile-:of thie-patent:

UNITED STATES PATENTS Nummr .Name Date 15 1,216,430 Smith .wmum.--.Aug.. 20, 1918 2,184,487 Clark Dem-26, ,1939

